Critical current density of YBa2Cu3Oy containing inclined columnar defects

Effects of columnar defects on the critical current density have been inves tigated by the in situ measurement of current-voltage characteristics for a c-axis oriented YBa2Cu3Oy, (YBCO) thin film after the irradiation with 200 MeV Au ions from the direction theta (irr) = 45 degrees off the e-axis, Th e dependences of the critical current density, J(c) on the magnetic field, the magnetic field angle, and the density of columnar defects are discussed . With increasing the density of the columnar defects, B-phi the contributi on of the columnar defects to the pinning force per unit volume, DeltaF(p), increases monotonically. The peak field for DeltaF(p) as a function of the magnetic field seems to be almost independent on B-phi. (C) 2001 Elsevier Science B.V. All rights reserved.